This invention relates to apparatus and methods for moving frameworks, such as window frames or sashes between manufacturing workstations such as between a welding machine and a workstation for “cleaning” of the frameworks.
It is known to provide for the welding of plastic window frames and in particular to provide a horizontal four-head welding machine capable of positioning plastic sections for two or more window frames for simultaneous welding. Subsequent to welding the window frames or sashes, it is typically necessary to clean the corners of the welded frames or sashes of excess material resulting from the welding process. This is commonly achieved with “corner cleaning machines”. It is also known to have automated processes and/or equipment which transfer the welded frames to the corner cleaning machine for processing.
Despite the existing capacity of known welding machines to weld two or more window frames or sashes simultaneously, known corner cleaning machines are typically only capable of cleaning one window frame or sash at a time and many known processes and apparatus are typically only capable of transferring one frame at a time to the corner cleaning machine. Accordingly it is a desired objective of the window frame manufacturing industry to be able to quickly and reliably transfer two welded window frames from the welding machine to a corner cleaning machine (or other work station) for carrying out a manufacturing step on the frames and to have the two frames processed or cleaned at substantially the same time. In this way the workstation or workstations downstream from the welding machine can operate at a speed that closely matches that achievable by the welding machine, thus achieving maximum efficiencies and increasing the output of the production line.
U.S. Pat. No. 6,086,703 issued Jul. 11, 2000 to Willi Sturtz Maschinenbau GmbH teaches a method and apparatus for manufacturing two plastic window frames at substantially the same time using a horizontal four-head welding machine. Plastic sections are clamped in the welding machine and are welded so as to create two window frames at the same time, these being arranged one above the other in the welding machine. After at least partial cooling, the welded window frames are released and removed. Support elements, which may be in the form of guide rails or rollers are moved at two opposite sides underneath each of the two window frames, these elements being located adjacent two welding heads. When these two welding heads are moved outwardly to release the frames, the frames rest on the support elements on one side of the machine and on the other side on the two other welding heads which are located on a movable carriage. This carriage is then moved horizontally to cause the frames to be moved at least partially out of the welding machine. The frames are then moved to an intermediate station on two conveyor belts located one above the other. The frames can then be moved to a workstation such as a bead cleaning machine.
Recent U.S. Pat. No. 6,006,408 issued Dec. 28, 1999 to Wegoma, Inc. teaches a widow frame weld seam cleaner having a fixed support head and a movable support head. This machine cleans only one window frame at a time. The window frame is engaged by an inner conveyor belt that moves the frame into and out of a first cleaning position for cleaning and machining the top corners of the window frame, and into and out of a second cleaning position for cleaning and machining the bottom corners. The inner conveyor includes fixed and movable fences, tabletop back fences, and clamps.
It is an object of one aspect of the invention to provide an improved apparatus for moving frameworks, such as window frames or sashes from a welding machine or other work station to another work station for further processing of the frameworks, this apparatus being able to efficiently move more than one framework at one time.
It is a further object of an aspect of this invention to provide an apparatus for moving frameworks from one work station to another work station for further processing, this apparatus being reliable and able to move the frameworks relatively quickly in a manner so they will not be damaged during transport to the next workstation.
It is an additional object of another aspect of the invention to provide an improved method of manufacturing plastic frameworks, such as window frames, using a four-head welding machine wherein two frameworks are welded simultaneously in the welding machine and then they are pulled simultaneously and horizontally to the next workstation for further manufacturing steps.